B.C. research brings possibility of end to seasonal flu shots with universal vaccine

Steve Mertl

Daily BrewMay 9, 2012

Every fall many of us wring our hands about whether to get the seasonal flu shot, even though it's estimated between 2,000 and 8,000 Canadians die each year of influenza and its complications.

Vaccination rates spiked during the H1N1 pandemic in 2009, which killed 14,000 people worldwide, but appear to have dropped again even though flu kills up to half a million people globally each year.

But research by University of British Columbia scientists has raised the tantalizing prospect of taking just one shot or series of shots that would provide lifetime protection from many flu viruses, the Vancouver Sun reports.

The research team led by Prof. John Schrader, Canada Research Chair in Immunology and director of UBC's Biomedical Research Centre, found the vaccine triggers antibodies that protect against many influenza viruses, including the lethal avian H5N1 "bird flu" strain.

Here's how Schrader explains it:

"The flu virus has a protein called hemagglutinin, or HA for short. This protein is like a flower with a head and a stem. The flu virus binds to human cells via the head of the HA, much like a socket and plug.

"Current flu vaccines target the head of the HA to prevent infections, but because the flu virus mutates very quickly, this part of the HA changes rapidly, hence the need for different vaccines every flu season."

But there was something different about the 2009 H1N1 vaccine that produced more broadly protective antibodies that could fight different flu viruses.

"This is because, rather than attacking the variable head of the HA, the antibodies attacked the stem of the HA, neutralizing the flu virus," said Schrader. "The stem plays such an integral role in penetrating the cell that it cannot change between different variants of the flu virus."

The way the human immune system works makes it hard for flu vaccines to create broadly protective antibodies against the HA stem, said Schrader, but the 2009 swine flu was different because people had not been exposed to a similar virus before.

Schrader said there's evidence a vaccine based on a mix of flu viruses circulating in animals but not humans should have the same effect.

The prospect of one or two shots, as with measles or polio, to create a long-term immunity carries the potential for making flu pandemics and seasonal flu outbreaks a thing of the past, saving hundreds of thousands of lives worldwide.

Schrader cautioned it will take years to test a universal flu vaccine suitable for general use.